The dash (--) is made by typing two hyphens (-). No spaces go in between the dash and the text. It is used...

a. to bracket off some explanatory information.

Example: "Even Cinderella's stepsisters-who were not nearly as lovely or virtuous as Cinderella--were allowed to go to the ball."

b. in the "drum roll" sense of the colon.

Example: "Prince Charming would find this mystery lady--even if he had to put the slipper on every other girl in the kingdom."

3. Vary your SENTENCE STRUCTURE

Don't say: "Cinderella saw her fairy godmother appear. She was dressed in blue. She held a wand. The wand had a star on it. She was covered in sparkles. Cinderella was amazed. She asked who the woman was. The woman said, 'I am your fairy godmother.' She said she would get Cinderella a dress and a coach. She said she would help Cinderella go to the ball."

Instead say: (there are multiple correct ways to rewrite this, but here's one) "Amazed, Cinderella watched as her fairy godmother appeared. The woman dressed in blue was covered in sparkles and carried a star-shaped wand. Cinderella asked the woman who she was, to which the woman replied, 'I am your fairy godmother." The fairy godmother would get Cinderella a dress and a coach; she would help Cinderella get to the ball."

4. Closely related to this, avoid CHOPPINESS

Don't say: "She scrubbed the floors. They were dirty. She used a mop. She sighed sadly. It was as if she were a servant ."

Instead say : (again, there are multiple ways to do this) "She scrubbed the dirty floors using a mop, as if she were a servant. She sighed sadly."

6. Be CONCISE

7. Use the VOCABULARY that you know.

Don't always feel you have to use big words. It is always better to be clear and use simple language rather than showing off flashy words you aren't sure about and potentially misusing them. This is not to say, however, that you should settle for very weak vocabulary choices (like "bad" or "big" or "mad").

8. But also work on expanding your VOCABULARY.

When reading, look up words you don't know. See how they're used. Start a list. Incorporate them into your writing as you feel comfortable and as they are appropriate.

9. Keep language FORMAL and avoid language of everyday speech.

Don't say: "Cinderella was mellow and good. She never let her stepmother get to her ."

Say instead: "Cinderella was mild-mannered and kind. She never let her stepmother affect her high spirits ."

So, essentially, when it comes to working on style, there are three things to remember:

Empower yourself with knowledge.

Learn to punctuate correctly, enhance your vocabulary, etc. Give yourself all the tools there are so that you are free to...

...Mix it up!

Avoid repetition of words and sentence structure. Variance promotes good "flow" and is more interesting for your reader.